SOURCE: Protherics PLC

April 27, 2007 13:46 ET

Protherics PLC announces Holding(s) in Company

Cheshire, UK -- (MARKET WIRE) -- April 27, 2007 --

                                 Protherics PLC

                    Notification of Major Interest in Shares

London, UK; Brentwood, TN, US; 27 April 2007 - Protherics PLC ("Protherics" or
the "Company"), the international biopharmaceutical company focused on critical
care and cancer, announces that the following notification of interest in the
ordinary share capital of the Company was received on 26 April 2007 from Aviva
plc.

1. Reason for the notification     (please tick the appropriate box or boxes)
An acquisition or disposal of voting rights
                                                                                               x
An acquisition or disposal of financial instruments which may result in the acquisition
of shares already issued to which voting rights are attached

An event changing the breakdown of voting rights

Other (please specify):___________________________________________

2. Full name of person(s) subject to the                    Aviva plc & its subsidiaries
notification obligation:

3. Full name of shareholder(s) (if different from Registered Holder:
2.):

                                                  BNY Norwich Union Nominees Limited
                                                  5,492,045*

                                                  Chase GA Group Nominees Limited
                                                  12,487,213*

                                                  Chase Nominees Limited
                                                  804,909*

                                                  CUIM Nominee Limited
                                                  4,914,014*

                                                  Vidacos Nominees Limited
                                                  76,113*

                                                  BNP Paribas - London
                                                  1,000,000

                                                  Chase Nominees Limited
                                                  724,217

                                                  CUIM Nominee Limited
                                                  3,550,079

                                                  State Street Nominees Limited
                                                  5,590,498

                                                  Vidacos Nominees Limited
                                                  5,770,150

                                                                            *denotes direct interest

4. Date of the transaction (and date on which the 25 April 2007
threshold is crossed or reached if different):

5. Date on which issuer notified:                 26 April 2007

6. Threshold(s) that is/are crossed or reached:   6% to 7% Change at Direct Interest level


7. Notified details:


A: Voting rights attached to shares
Class/type of     Situation previous to    Resulting situation after the triggering transaction
shares            the Triggering
                  transaction
if possible using Number of   Number of    Number of     Number of voting rights     % of voting
the ISIN CODE     Shares      Voting       shares                                    rights
                              Rights       Direct        Direct        Indirect      Direct   Indirect
Ordinary Shares


GB0007029209      39,840,897  39,840,897   23,774,294    23,774,294    16,634,944    7.01%    4.91%


B: Financial Instruments

Resulting situation after the triggering transaction
Type of financial   Expiration date Exercise/ Conversion      Number of voting rights    % of voting
instrument                          Period/ Date              that may be acquired if    rights
                                                              the instrument is
                                                              exercised/ converted.


                                                  N/A


Total (A+B)
Number of voting rights                           % of voting rights

40,409,238                                        11.92%


8. Chain of controlled undertakings through which the voting rights and/or the financial instruments are
effectively held, if applicable :
                                                  See Section 3


Proxy Voting:

9. Name of the proxy holder:                                           See Section 3

10. Number of voting rights proxy holder will cease to hold:

11. Date on which proxy holder will cease to hold voting rights:


12. Additional information:                Figures are based on a total number of voting rights  of
                                           339,128,755



                                   |  Ends  |



For further information please contact:

Protherics
Nick Staples, Director of Corporate Affairs                                     +44 (0) 7919  480510
Julie Vickers, Company Secretary                                                +44 (0)1928 518010

Financial Dynamics - press enquiries
London: Ben Atwell, Anna Keeble                                                 +44 (0) 20 7831 3113
New York: John Capodanno, Jonathan Birt                                         +1 212 850 5600

Or visit  www.protherics.com



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